$fontsize: 37.5;
@function px2rem($px){
    @return ($px / $fontsize) + rem;
}

@mixin center() {
    display: flex;
    justify-content: center;
    align-items: center;
}

@mixin left() {
    display: flex;
    justify-content: flex-start;
    align-items: center;
}

.icon {
    color: #333;
    font-size: px2rem(50);
}